The present invention relates to error detecting/correcting codes.
A useful class of error detecting/correcting codes are the so-called Reed-Solomon (RS) codes. In a typical application, a stream of input bits are divided into RS input words. The RS encoder generates a frame of RS output words generated in response to the RS input words. Where, for example, the RS code is a so-called systematic code, the output frame is comprised of the RS input words followed by one or more redundant words generated as a function of the RS input words.
In a typical application, the values of the RS encoder output words are communicated from a transmitter to a receiver over a communications channel by using a predetermined constellation of channel symbols to represent the various RS encoder output word values. Moreover, if in the particular application it is possible that the transmitted symbols will be "rotated" as the result, for example, of a so-called phase hit or other channel phenomenon, one or more of the output bits of the RS encoder can be differentially encoded so as to correct for this situation, as is well known. And in the receiver, the signal received from the channel will be differentially decoded prior to RS decoding.